1  // compressed_output.h -- compressed output sections for gold  -*- C++ -*-
       2  
       3  // Copyright (C) 2007-2023 Free Software Foundation, Inc.
       4  // Written by Ian Lance Taylor <iant@google.com>.
       5  
       6  // This file is part of gold.
       7  
       8  // This program is free software; you can redistribute it and/or modify
       9  // it under the terms of the GNU General Public License as published by
      10  // the Free Software Foundation; either version 3 of the License, or
      11  // (at your option) any later version.
      12  
      13  // This program is distributed in the hope that it will be useful,
      14  // but WITHOUT ANY WARRANTY; without even the implied warranty of
      15  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      16  // GNU General Public License for more details.
      17  
      18  // You should have received a copy of the GNU General Public License
      19  // along with this program; if not, write to the Free Software
      20  // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
      21  // MA 02110-1301, USA.
      22  
      23  // We support compressing .debug_* sections on output.  (And,
      24  // potentially one day, other sections.)  This is a form of
      25  // relaxation.  This file adds support for merging and emitting the
      26  // compressed sections.
      27  
      28  #ifndef GOLD_COMPRESSED_OUTPUT_H
      29  #define GOLD_COMPRESSED_OUTPUT_H
      30  
      31  #include <string>
      32  
      33  #include "output.h"
      34  
      35  namespace gold
      36  {
      37  
      38  class General_options;
      39  
      40  // Read the compression header of a compressed debug section and return
      41  // the uncompressed size.
      42  
      43  extern uint64_t
      44  get_uncompressed_size(const unsigned char*, section_size_type);
      45  
      46  // Decompress a compressed debug section directly into the output file.
      47  
      48  extern bool
      49  decompress_input_section(const unsigned char*, unsigned long, unsigned char*,
      50  			 unsigned long, int, bool, elfcpp::Elf_Xword);
      51  
      52  // This is used for a section whose data should be compressed.  It is
      53  // a regular Output_section which computes its contents into a buffer
      54  // and then postprocesses it.
      55  
      56  class Output_compressed_section : public Output_section
      57  {
      58   public:
      59    Output_compressed_section(const General_options* options,
      60  			    const char* name, elfcpp::Elf_Word flags,
      61  			    elfcpp::Elf_Xword type)
      62      : Output_section(name, flags, type),
      63        options_(options)
      64    { this->set_requires_postprocessing(); }
      65  
      66   protected:
      67    // Set the final data size.
      68    void
      69    set_final_data_size();
      70  
      71    // Write out the compressed contents.
      72    void
      73    do_write(Output_file*);
      74  
      75   private:
      76    // The options--this includes the compression type.
      77    const General_options* options_;
      78    // The compressed data.
      79    unsigned char* data_;
      80    // The new section name if we do compress.
      81    std::string new_section_name_;
      82  };
      83  
      84  } // End namespace gold.
      85  
      86  #endif // !defined(GOLD_COMPRESSED_OUTPUT_H)